GOES-R & JPSS: The Future of Weather Satellites

VIIRS

There are certain things you can count on seeing in October. Great post-season baseball! Pumpkin flavored everything! Halloween! Super Typhoons?! To celebrate the successful launch of Himawari-8 from Japan last night, I thought it would be appropriate to post on this latest super typhoon.

Super Typhoon Vongfong has intensified impressively in the last 24 hours after passing through the Marianas Islands yesterday as a Category 2 typhoon with winds ~105 mph. As of 1500 UTC, the Joint Typhoon Warning Center initialized Vongfong as a 135 kt (155 mph) super typhoon and the Satellite Analysis Branch (SAB) of NESDIS classified it as a T7.0, which would support Category 5 winds. Since that time, there has been a slight warming of the cloud tops surrounding the eye, but there is no strong indication of an eyewall replacement cycle, yet. It’s possible that Vongfong may still strenghten some in the next 12-24 hours.

The satellite animation above shows Vongfong’s rapid organization overnight with intermittent lightning bursts in the eyewall during the rapid intensification. Typically, hurricanes and typhoons don’t exhibit much lightning due to the lack of convective available potential energy (CAPE) and dry air near the strongest thunderstorms. During intense thunderstorm growth, most notably in the outer rain bands, there can be some graupel (soft hail/snowballs) which supports lightning, but the inner core is usually quieter (of course, this varies based on basin). We have seen this before in the West Pacific (see posts on Haiyan and Rammasun).

89GHz RGB image from AMSR-2 on JAXA valid on 10/07/14.

89GHz RGB image from GMI on GPM valid on 10/07/14.

The two microwave image passes above show the convective structure of Vongfong under the clouds where the red coloring indicates heavier precipitation or convection. These high resolution microwaves images are used by JTWC, SAB, and the National Hurricane Center when classification are being made, especially for fixing the initial center positions.

Another interesting way of looking at the microwave imagery is with lightning overlaid. The lightning strikes for the previous 30 minutes were overlaid on this 0719 UTC Tropical Rainfall Measurement Mission (TRMM) satellite pass. As you can see, the lightning matches up quite well with the red colorings (convection). Notice the lightning cluster in the southeast eyewall!

The Day-Night Band image from VIIRS on S-NPP valid at 1703 UTC on 10/07/14. Courtesy of Dan Lindsey (NESDIS/STAR)

Finally, this incredible Day-Night Band (DNB) image was captured by the S-NPP satellite this afternoon. That is not a traditional visible satellite image. . .that is from the moon light! The Proving Grounds receive DNB imagery from NASA SPoRT and CIMSS on a routine basis to help forecasters identify significant features and help with center fixes of tropical cyclones, similar to the microwave imagery.

The storms that ravaged the southern United States this past week not only produced deadly severe weather, but also incredible flooding. Figure 1 shows parts of the Florida Panhandle and southern Alabama received in excess of 10 inches of rain on Tuesday, April 29 alone!

A previous blog post introduced the Overshooting Top Detection product and explained its utility in severe weather situations. Overshooting tops are also indicators of where heavy rainfall may be occurring. Furthermore, the constant presence of overshooting tops over a particular location over an extended period of time may indicate a prolonged period of heavy rainfall, which could lead to flooding.

The animation in Figure 2 shows GOES-East IR imagery with overshooting top detection’s overlaid from the afternoon of the April 29 into the early morning hours of the April 30. During much of this period, GOES-East was in Rapid Scan Mode, meaning images were often available every 5-10 minutes (instead of 15). Notice the persistence of overshooting tops centered over the Mobile area throughout the period, where copious amounts of rainfall were recorded. By about 09Z, a downward trend in overshooting top detection’s had begun as the storm system shifted eastward and weakened. The Overshooting Top Detection product provides a day/night capability for forecasters to easily identify where within a convective system the strongest updrafts are occurring, and where severe weather and/or heavy rainfall may be occurring given other meteorological factors.

Figure 3 shows this same system during the early morning hours of April 30 at much higher resolution. This is a 375 m IR image taken with the Suomi NPP VIIRS instrument. Notice the visibility of features that aren’t easily seen in current GOES IR imagery such as gravity waves and overshooting tops.

The spatial resolution of infrared (IR) polar imagery (e.g., Suomi NPP VIIRS and MODIS) is currently superior to similar geostationary data over North America (~1km vs 4km). Unfortunately, there are relatively few polar passes a day over the contiguous United States. At best, there would be 2 passes over any one location every 12 hours for each polar satellite. This is one reason why it is challenging to introduce operational forecasters to the advantages in using this imagery.

This will all change over the next year with the National Weather Service’s (NWS) second generation Advanced Weather Interactive Processing System (AWIPS2), and the use of polar imagery will become more and more common within NWS Forecast Offices. This is because AWIPS2 will allow the forecaster to overlay multiple images to create GOES/POES hybrid satellite loops.

In the image below, this capability is shown using IR imagery from GOES-13 (10.7 μm), MODIS (~11.0 μm), and Suomi NPP VIIRS (11.45 μm) between 0615 and 0801 UTC on 28 March 2014 over the Southern Mississippi Valley.

When polar imagery is available from MODIS or VIIRS, it is overlaid on the GOES imagery which allows the forecaster to take advantage of the greater spatial resolution of the polar imagery. In the example shown above, there are GOES-13 images at 0615, 0631, and 0645 UTC, followed by a VIIRS image at 0655 UTC, two more GOES-13 images at 0715 and 0731 UTC, a MODIS image at 0740 UTC, and one more GOES-13 image at 0801 UTC. As the forecaster cycles through the images, you can envision how this capability would be beneficial. The increased spatial resolution from MODIS and VIIRS allows important details to be extracted which include the location and strength of updrafts/overshooting tops and the location where new convection is forming on the southwestern flank of the MCS. In addition, when deep convection is present, the parallax (GOES pixels are displaced slightly poleward from their correct position) that occurs with geostationary satellites is magnified and the polar imagery “corrects” the location for the forecaster. To see the full impact of these hybrid images, click on the image for a full resolution version.

AWIPS2 is currently being installed at NWS forecast offices throughout the country. +

This was one of those storms that people will talk about for years, especially those that were directly affected by it. It all started with three separate shortwaves that all phased together once off the Mid-Atlantic coast, far enough offshore to limit any direct effects save for some unusual late season snow and gusty winds the next day. The highest impact area included Cape Cod, Nantucket, Nova Scotia, and New Foundland. I’m sure any ships that were in the vicinity were not happy with this situation!

GOES-Sounder RGB Air Mass animation valid 03/24/14-03/26/14.

The evolution of the nor’easter can be seen in the GOES Sounder RGB Air Mass animation above. A southern stream system originating in the Gulf of Mexico moved east of Florida while two other shortwaves dropped southeast out of Canada. All of the pieces combined near the North Carolina coastline, but the explosive deepening took place as the combined system moved northeast away from the Mid-Atlantic. There appears to be a few stratospheric intrusions, but the most impressive intrusion occurs with the final shortwave as noted by the dark oranges and reds that appear at the end of the day on 03/25. When models are forecasting a phasing situation, this product can be quite useful in identifying the features and observing the stratospheric drying seemingly “bleed” from one shortwave to the other.

The two MODIS RGB Air Mass products above show the nor’easter near peak intensity. Notice how distinct the gradient between oranges and greens is in this image, almost as though you can see the upper portion of the frontogenesis, well behind the actual front. The intensity of the stratospheric intrusion is quite evident by the dark pinks near the center of the cyclone. The second image shows the wind field overlaid from ASCATB. Notice the large area of hurricane force winds (red wind barbs) near the bent-back front, in the comma-head of the cyclone. This area of wind affected parts of Southeast Massachusetts, including Nantucket where winds gusted from 60-85 mph. Nantucket recorded a wind gust of 82 mph and about 10″ of snow. Meanwhile, Nova Scotia bore the brunt of this beast with wind gusts of 129 mph at the Bay of Fundy and 115 mph in Wreckhouse. Waves were equally impressive with altimeter readings between 40-50 ft and a buoy report of 52.5 ft.

Another interesting aspect of this storm was the two distinct areas of thunderstorms that erupted. I overlaid the OPC and TAFB offshore zones for reference. Notice well east of the Bahamas there are possible supercell thunderstorms associated with the southern shortwave energy. Meanwhile, as the strong northern stream shortwaves exit the NC coastline, two areas of thunderstorms developed with the easternmost storm exhibiting supercell characteristics. Although the lightning was not as intense with this northern area, I would speculate that the storms were associated with very strong wind gusts due to the dry air associated with the stratospheric intrusion.

VIIRS Visible image valid at 1719 UTC on 03/26/14.

VIIRS Visible image with the 18 UTC OPC surface analysis overlaid.

I’ll finish this entry with two VIIRS Visible images above showing the majestic beauty of this nor’easter. The 18 UTC OPC surface analysis depicts the storm at a maximum intensity of 955 mb, after a 45 mb drop in 24 hours! This qualifies as one of the most explosive cyclones on record. Another tidbit. . .this was the strongest storm in this part of the Atlantic since Hurricane Sandy (2012).

Well, that didn’t take long. . .a week ago we were enduring the wrath of tornadoes through the Plains and Midwest and this week the tropics, not wanting to be out-done, decided to chip in. Tropical Storm Andrea formed late yesterday and has decided to make an early visit to Florida.

I wanted to continue the theme of showing off the capabilities of the Overshooting Top Detection and Lightning Density products that forecasters at the Satellite Proving Ground for Marine, Precipitation, and Hazardous Weather Applications are evaluating. Andrea has put on an interesting show today as you’ll see below.

The Overshooting Top Magnitude Product overlaid on GOES-14 Infrared imagery valid on 06/06/13 (click on image to animate).

The Overshooting Top (OT) Magnitude product (developed by Kris Bedka – SSAI) has been getting quite a workout today over the Gulf and near-shore waters of Florida. Many of the OTs have exhibited a 9-15 degree difference between the OT and the cirrus shield. One OT from early in the loop nearly exceeds the scale I set for the product! Notice how most of the strong OT signatures are seen over water with very few over land in this case. Although wind is expected with a tropical cyclone, these OTs may indicate localized areas of enhanced wind gusts that mariners would have to be made of aware of, even being far from Andrea’s center.

The new experimental GLD-360 Lightning Density product has been very revealing today as it helps to contrast the difference between lighting activity associated with a tropical system and activity associated with continental thunderstorms. Notice how the lighting activity with Andrea starts out relatively quiet, but increases as a squall line develops northwest of Cuba and the Keys. Even so, the lightning activity is not overly impressive as this is 30-minutes of binned lighting strokes. The thunderstorms near the center of Andrea are practically absent of lightning during this entire animation. Meanwhile, the thunderstorms over Louisiana and Texas show very intense lightning activity near the end of the loop.

Pop quiz: why the contrast?

Finally, my email was greeted by some beautiful imagery of Andrea from overnight courtesy of William Straka III from CIMSS at the University of Wisconsin. I have included a couple of these images below for your enjoyment.

Andrea as seen on from the Day-Night Band from VIIRS on the Suomi-NPP satellite valid at 0726 UTC on 06/06/13.

This image from the Day-Night Band on VIIRS is very cool as you are seeing the cloud pattern associated with Andrea with very low amounts of atmospheric light known as “air glow”. The bright spots on the Florida peninsula are the city lights. It’s amazing that even with minimal light, you can still get a feel for the vertical dimensions of the clouds.

Enhanced Infrared imagery from the Suomi-NPP satellite valid at 0726 UTC on 06/06/13.

I received some very interesting imagery from William Straka III (CIMSS/SSEC/U. of Wisconsin-Madison) the other day which shows a satellite view of the recent Aurora Borealis event in Southern Canada, but also seen in the northern U.S. The Suomi NPP VIIRS Day-Night Band picked up the Aurora event rather well as you can see below. Although not necessarily meteorological, it’s amazing what this new instrument will be able capable of providing over the next few years.

Suomi NPP VIIRS Day-Night Band image of the Aurora Borealis valid at 0418z on 11/14/12. (Image courtesy of William Straka III (CIMSS/SSEC/U. of Wisconsin-Madison)

Suomi NPP VIIRS Day-Night Band image of the Aurora Borealis valid at 0603z on 11/14/12. (Image courtesy of William Straka III (CIMSS/SSEC/U. of Wisconsin-Madison)

Suomi NPP VIIRS Day-Night Band image of the Aurora Borealis valid at 0746z on 11/14/12. (Image courtesy of William Straka III (CIMSS/SSEC/U. of Wisconsin-Madison)

Suomi NPP VIIRS Day-Night Band image of the Aurora Borealis valid at 0927z on 11/14/12. (Image courtesy of William Straka III (CIMSS/SSEC/U. of Wisconsin-Madison)

I have a short post today to show you another unique way of using the Day-Night Band on the Suomi NPP VIIRS instrument. By having this low-light band available, it will now be possible to monitor the extent of power outages from space! The short animation below (click on image to animate) shows the NYC/NJ area days before Sandy’s arrival and last night. As you can see, there are many areas of northern-coastal NJ that are in the dark still and possibly will be for days or weeks. The last report I heard from family in coastal NJ is that some people may not get power for up to a month! Meanwhile, some towns like Pt. Pleasant, parts of Toms River down to Atlantic City are slowly getting their power back. The barrier islands will not have power or access for a long, long time.

Suomi NPP VIIRS Day-Night Band image showing before and after power outage effects in NYC and NJ. The image is courtesy of William Straka III from CIMSS/SSEC at the University of Wisconsin-Madison.

I plan on having a few GOES-14 SRSO and RGB Air Mass animations ready for post tomorrow or early next week, so stay tuned!